text: /**** header files ****/
  
  #include <unistd.h>  // used for read()
  #include <termios.h> // used for tcgetattr() and tcsetattr()
  #include <stdlib.h>
  #include <errno.h>
  #include <stdio.h>  // for printf()
  #include <ctype.h>  // for iscntrl()
  
  
  /**** defines - macros ****/
  
  #define CTRL_KEY(k) ((k) & 0x1f)
  
  
  /**** data ****/
  
  struct termios orig_termios;
  
  
  
  /**** terminal ****/
  
  void die(const char *s)
  {
      perror(s);
      exit(1);
  }
  
  
  void disableRawMode()
  {
      if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1)
      {
          die("tcsetattr");
      }   
  }
  
  
  void enableRawMode()
  {
      if (tcgetattr(STDIN_FILENO, &orig_termios) == -1)
      {
          die("tcgetattr");
      }
  
      atexit(disableRawMode);
  
      struct termios raw = orig_termios;
      
      raw.c_iflag &= ~(BRKINT | INPCK | ICRNL | ISTRIP | IXON);
      raw.c_oflag &= ~(OPOST);
      raw.c_cflag |= (CS8);
      raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
      raw.c_cc[VMIN] = 0;
      raw.c_cc[VTIME] = 1;
      tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
  
      if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) 
      {   
          die("tcsetattr");
      } 
  
  }
  
  
  
  /**** init ****/
  
  int main()
  {
      enableRawMode();
  
      while (1) 
      {
          char c = '\0';
          if (read(STDIN_FILENO, &c, 1) == -1 && errno != EAGAIN)
          {
              die("read");
          }
  
          if (iscntrl(c))
          {
              printf("%d\r\n", c);
          }
          
          else
          {
              printf("%d ('%c')\r\n", c, c);
          }
  
          if (c == CTRL_KEY('q'))
          {
              break;
          }
      }
  	
      return 0;
  }
  